As aircraft fly at subsonic, transonic or supersonic speeds, aero-optical disturbances in the air flow field surrounding the aircraft are created by surfaces of the aircraft moving through the air. These aero-optical disturbances will vary for each shape of an aircraft and as the aircraft changes speed, altitude and operational maneuvers. At higher speeds, such as supersonic, aero-optical disturbances in the air flow field surrounding the aircraft will include not only wavefront disturbances but also shock boundaries. These aero-optical disturbances created in the air flow field will affect the performance and/or accuracy of optical instrumentation which are carried by the aircraft and are used to receive optical data and/or emit optical energy.
The problems created by these aero-optical disturbances include tracking accuracy of optical trackers, blurred image quality of surveillance sensors, imprecise pointing of laser systems and reduced beam quality of laser energy propagated through the aero flow field containing the aero-optical disturbances. Gathering accurate spatial and temporal data of these aero-optical disturbances from the flow field of the aircraft will enable the design of high performance and accurate optical equipment such as optical trackers, optical imaging, laser radar, precise aiming equipment for lasers and laser weapon systems. With accurate measured data of these disturbances from the air flow field design criteria can be implemented into these devices to compensate for the optical deviations created by these aero-optical disturbances.
There is a need to be able to measure and collect aero-optical disturbance data for each different shape of air craft. Moreover, since the aero-optical disturbances change for various speeds, altitudes and maneuver configurations of the aircraft, the data will need to be compiled for changes in these parameters as well. Thus, to obtain reliable modeling data for a particular aircraft, measurements of the aero-optical disturbances would best be acquired through appropriate equipment for measuring and collecting such aero-optical data to be secured to the aircraft with the aircraft flown through these variations of parameters of speed, altitude and while conducting various maneuvers.
The aero-optical disturbances to be measured and collected for various aircraft, could include subsonic, transonic and supersonic speeds up to at least Mach 2. The measurements of the aero-optical disturbances are needed for the aircraft operating in an altitude envelope ranging from sea level to seventy-five thousand feet. Additionally, the measurements of the aero-optical disturbances will be needed from the aircraft conducting various maneuvers which impart as much as 3 g of force on the aircraft. All of this data will need to be accurately measured in order to provide reliable modeling for each aircraft that will eventually carry optical equipment, as discussed above.
In the past, aero-optic measurements had been obtained by using wind tunnels or by using large aircraft in flight to create the air flow fields. The use of wind tunnels to replicate the high speeds of a particular aircraft, and more particularly, supersonic speeds greater than Mach 1 presented complications. In particular, shock waves impacting a wall of the tunnel disrupt the replication and therefore fidelity of an aero-optical disturbance that would normally occur in open ambient air flow field flight. Because measurement equipment for aero-optical disturbances are generally large and complex equipment, larger aircraft have been needed to carry the equipment. The use of larger aircraft also presented an additional problem with their limited speed ranges. With the limited speed of these larger aircraft, measuring aero-optical disturbances at higher rates of speed were limited if not completely prevented. Moreover, the large complex instrumentation for measuring the aero-optic disturbances restricted the positioning or location of such equipment on the aircraft, thereby limiting the collection of data of air flow field disturbances to the limited positions on the aircraft to accommodate the large complex equipment.
In order to measure and compile the needed data regarding the aero-optic disturbances to provide modeling design criteria for optical instrumentation, measuring instrumentation needs to be developed that is compact. Compact measuring instrumentation can be secured to smaller aircraft such as fighter aircraft that can travel at a wide range of speeds from subsonic to supersonic. Also, a compact configuration will enable the measuring equipment to be secured to numerous different positions on the aircraft. This will enable measurements to be made from positions which would replicate the positions in which optical instrumentation may be later positioned. The compact size will also help to prevent creating unwanted aerodynamic imbalance of the aircraft.
A compact configuration of the measuring instrumentation will facilitate the measuring and collection of disturbance data for many different aircraft that will need to travel through a wide range of speeds and altitudes as well as with moving through various maneuvers. The compact configuration of the measuring equipment will provide the needed spatial and temporal data of the aero-optical disturbances in the flow field of that aircraft so as to establish the modeling in order to design the optical systems and/or flow control devices the aircraft will ultimately carry to operate within and/or mitigate these aero-optical disturbances.
The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings.